In recent years, with rapid spread of an advanced communication infrastructure represented by the Internet, collection and distribution of information between computers (e.g., between a server and a client) are generally performed according to a communication protocol such as the HTTP (Hypertext Transfer Protocol), the IIOP (Internet Inter ORB Protocol) or the FTP (File Transfer Protocol). However, recently, the following problems have arisen.
(1) In information collection and distribution through the Internet, illegal acts such as falsification, wiretapping, and pretending may be performed. For this reason, an operation load on a system manager for ensuring security tends to increases.
(2) With an increase in the number of accesses with an increase of the number of users, or an increase in the quantity of information (image data, audio data, computer program, and the like) to be collected and distributed, a load on a network increases.
(3) With an increase in the number of client device, a load on a server for controlling collection and distribution of information increases.
Accordingly, means and method for effectively solving the above-mentioned problems is in demand.
FIG. 22 is a block diagram showing an example of configuration of a conventional information collection and distribution system. In this diagram, a client/server type information collection and distribution system which is structured through a network having a LAN (Local Area Network)—WAN (Wide Area Network)—LAN form is shown. A main office network system 10 is an in-house system, and is constituted by a main office server 11, a LAN 13, and a fire wall 14.
The main office server 11 comprises a function of distributing information (e.g., an application program 12) to an employee 0 client 330 to an employee n client 33n (to be described later) and a function of collecting information from the employee 0 client 330 and the employee n client 33n. The main office server 11 is connected to the LAN 13. The fire wall 14 is used to prevent illegal access to the main office network system 10 from an external system, and is designed to pass only information or a protocol to which a security is given. The LAN 13 is an in-house network installed in the main office, and is connected to the Internet 20 through the fire wall 14.
A branch office network system 30 is an in-house system structured in a branch office, and is constituted by a fire wall 31, a LAN 32, and an employee 0 client 330 to an employee n client 33n. The fire wall 31 is used to prevent illegal access to the branch office network system 30. The LAN 32 is an in-house network installed in the branch office, and is connected to the Internet 20 through the fire wall 31. The employee 0 client 330 to the employee n client 33n are computers which are arranged for an employee 0 to an employee n (not shown) in the branch office, respectively, and are connected to the LAN 32.
Operation of the information collection and distribution system shown in FIG. 22 will be described below with reference to a sequence chart shown in FIG. 23. In step F1 in FIG. 23, the main office server 11 transmits an application program 12 as a communication block to the employee 0 client 330 through the LAN 13, the fire wall 14, the Internet 20, the fire wall 31, and the LAN 32 (to be referred to as a network hereinafter) to distribute the application program 12 as information to the employee 0 client 330 to the employee n client 33n by a circulation system.
When the communication block (application program 12) is received, in step F2, the employee 0 client 330 stores a copy of the application program 12 in a storage device (not shown), and then notifies the main office server 11 of a progress status of distribution through the network. Here, the status is that the communication block is received, i.e., that the communication block is circulated to the employee 1 client 331 which is a circulation destination.
In step F3, the employee 0 client 330 transmits (circulates) a communication block to the employee 1 client 331 which is the next circulation destination through the LAN 32. When the communication block is received, in step F4, the employee 1 client 331 stores a copy of the application program 12 in the storage device, and then notifies the main office server 11 of a progress status of distribution through the network.
In step F5, the employee 1 client 331 transmits (circulates) the communication block to the employee 2 client 332 which is a circulation destination through the LAN 32. Thereafter, the clients subsequent to the employee 2 client 332 notify the main office server 11 of statuses, and sequentially transmit communication blocks to clients which are next circulation destinations.
When a communication block is transmitted to the employee n client 33n which is the final circulation destination, the employee n client 33n, the employee n client 33n stores a copy of the application program 12 in the storage device, and then notifies the main office server 11 of a progress status of distribution through the network.
In this manner, in the conventional information collection and distribution system, a communication program is transmitted to the employee 0 client 330 which represents the employee 0 client 330 and the employee n client 33n, and communication blocks are sequentially circulated to the employee 0 client 330→the employee 1 client 331→ . . . → the employee n client 33n in the branch office network system 30, so that information distribution is realized.
On the other hand, in the conventional information collection and distribution system, status notifications are performed from the employee 0 client 330 to the employee n client 33n, respectively, so that collection of pieces of information is realized on the main office server 11 side.
FIG. 24 is a block diagram showing another example of the configuration of a conventional information collection and distribution system. The same reference numerals as in FIG. 22 denote the same parts in FIG. 24. In FIG. 24, a dedicated server 40 for controlling collection and distribution on the branch office network system 30 side is newly connected to the LAN 32.
Operation of the information collection and distribution shown in FIG. 24 will be described below with reference to the sequence diagram shown in FIG. 25. In step G1 shown in FIG. 25, the main office server 11 transmits the application program 12 to the dedicated server 40 through the Internet 20 to distribute the application program 12 as information to the employee 0 client 330 to the employee n client 33n by a circulation system.
When the application program 12 is received, in step G2, the dedicated server 40 transmits (circulates) the application program 12 to the employee 0 client 330 which is the first circulation destination through the LAN 32. When the application program 12 is received, in step G3, the employee 0 client 330 stores a copy of the application program 12 in the storage device, and then notifies the dedicated server 40 of a progress status of distribution through the LAN 32. Here, the status is that the application program 12 is distributed.
In step G4, the dedicated server 40 transmits the application program 12 to the employee 1 client 331 which is the next circulation destination through the LAN 32. When the application program 12 is received, in step G5, the employee 1 client 331 stores a copy of the application program 12 in the storage device, and then notifies the dedicated server 40 of a progress status of distribution through the LAN 32. Thereafter, transmission of the application program 12 from the dedicated server 40 to the client which is a circulation destination and status notification from the client to the dedicated server 40 are sequentially performed.
When the application program 12 is transmitted to the employee n client 33n which is the final circulation destination in step G6, in step G7, the employee n client 33n stores a copy of the application program 12 in the storage device, and then notifies the dedicated server 40 of a progress status of distribution through the LAN 32.
In this manner, when distribution (circulation) to the employee 0 client 330 to the employee n client 33n is completed, in step G8, the dedicated server 40 notifies the main office server 11 of an entire status obtained by collecting status notifications which are respectively received from the employee 0 client 330 to the employee n client 33n through the network.
Techniques related to the information collection and distribution by the circulation system are disclosed in Japanese Unexamined Patent Publication No. 9-8801, Japanese Examined Patent Publication No. 2740105, Japanese Unexamined Patent Publication No. 6-216934 and Japanese Unexamined Patent Publication No. 11-25185, respectively.
However, in the information collection and distribution system shown in FIG. 22, the status notifications are respectively performed from the employee 0 client 330 to the employee n client 33n to the main office server 11. For this reason, an amount of traffic on the network increases in proportion to the number of clients. Accordingly, the network and the main office server 11 disadvantageously receive a heavy load.
In addition, the information collection and distribution system shown in FIG. 22 is designed such that status notifications are respectively performed from the employee 0 client 330 to the employee n client 33n. For this reason, it is not preferable that traffic passes through the fire wall 31 every status notification. Therefore, a load on a system manager for securing a security disadvantageously increases.
On the other hand, in the information collection and distribution system shown in FIG. 24, the dedicated server 40 is arranged to perform status notifications to the main office server 11 at once. For this reason, load on the Internet 20 and the LAN 13 are reduced, and the information collection and distribution system is more secured as compared to the information collection and distribution system shown in FIG. 22.
However, in the information collection and distribution system shown in FIG. 24, status notifications are still performed from the employee 0 client 330 to the employee n client 33n to the dedicated server 40, respectively. For this reason, a heavy load disadvantageously acts on the LAN 32. In the information collection and distribution system shown in FIG. 24, the dedicated server 40 must be arranged independently of the employee 0 client 330 to the employee n client 33n, so that the costs disadvantageously increase.
In addition, in the information collection and distribution systems shown in FIG. 22 and FIG. 24, the circulation system is employed between the employee 0 client 330 to the employee n client 33n. For this reason, a long period of time is disadvantageously required to end all the collection and distribution.